TB 9-4920-454-35
NOTE
When LED display is flashing, an over-range condition exists.
The reading is incorrect.
a. Performance Check
TEST INSTRUMENT
CALIBRATOR
CHECK CABLE
OUTPUT
RED
HI
LO
BLUE
AIRCRAFT T.C.
THERMOMETER
BH277 *
LEADS
RED
-
BH123-3 *
(SWITCH BOX)
+
BLUE
JETCAL
BH450 *
* SUPPLIED WITH TEST INSTRUMENT
(2) Position controls as listed in (a) through (e) below:
(a) T/C INPUT switch to CHECK CABLE.
(b) FUNCTION SELECT switch to TRIM.
(c) TEMPERATURE CAL ADJ to mid-position.
(d) TEMPERATURE switch to OPERATE.
(e) SW-5 switch (located on BH 123-3 switch box) to JETCAL.
(3) Place thermometer adjacent to calibrator OUTPUT terminals. Wait 10 minutes
for thermometer to stabilize and record ambient temperature.